Saving the traditional box sash window
publication date: Jul 10, 2008
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author/source: David Harris
The traditional timber box sash window has been an intrinsic part of our architectural heritage since the seventeenth century. Sir Christopher Wren was reputedly a great fan and the window’s elegant styling later became a distinctive feature of classic Georgian and Victorian buildings.
Over the years, its design has naturally been developed and refined with the introduction of modern materials and manufacturing techniques, but its appeal remains timeless. As sliding sash windows continue to be popular, it is increasingly important that builders protect their aesthetic integrety and, where possible, try to preserve the original sashes in some of our older properties.
Preserve or replace?
Up until now, when faced with old and degrading sash windows, the options have been either to rip out the old and replace them with completely new sash windows or to painstakingly repair the existing windows.
Full frame replacement has the obvious advantage of automatically upgrading the thermal and technical performance of the windows, but replacing elegant ‘olde-world’ sash windows with unsightly PVC-u sections can have a devastating effect on the appearance a building. Replacement with like-forlike or similar timber or timber based composite replacement windows is much more appropriate.
Alternatively, some sash windows can be repaired quite easily. For instance, some of the common failures such as flaky paintwork, degraded putty, sticking sashes and broken glass panes can be dealt with relatively easily and draught seals, broken sash cords and pulleys can be replaced without too much trouble.
However, extensive repairs to a badly damaged and degraded sash window can become an elaborate and long drawn out process and, unless we are looking at a grade II listed building, it may not always be worth the time, expense, effort and specialist treatment required.
An alternative option
Fortuntately, there is now a sustainable and cost effective alternative to both undertaking extensive repair work or full frame replacement, which will preserve the character of the original window.
As traditional box sash windows are set back into the brickwork, even when the sash itself has degraded and rotted away, the outer frame is often protected from the elements and is usually still in a relatively good condition and therefore worth saving.
Andersen Windows’ new Woodwright® ‘insert replacement window’ is a wooden window that allows builders to replace the rotten and broken down sashes, whilst leaving the trim and frame of the original window completely intact.
This practical alternative saves massively on time, labour and expense as the installation is quick and simple - not necessarily even requiring a specialist installer.
As the ‘insert replacement window’ already incorporates fully adjusted block and tackle spring balances, there is no need for any complicated repair work, fiddly balance adjustment or replacement of the weights themselves. It is a completely self-contained unit.
The end result is seamless – a traditional wood window with a choice of pine, oak, maple or white interior finishes and white, Sandtone (a neutral beige), Terratone® (an earth colour) and Forest Green exteriors to complement the original frame and building.
However, what makes the ‘insert replacement window’ so revolutionary is its use of a pioneering new composite material in the sash called Fibrex®.
Fibrex® is made from a patented blend of reclaimed pine wood fibre bonded with a thermoplastic polymer, which not only delivers a strength, rigidity and thermal performance equal to pure wood but, as each wood fibre is coated with polymer, it is also resistant to flaking, blistering, peeling, cracking and corrosion and does not require external painting.
Being made from 50% recycled waste, Fibrex® is also an extremely eco-friendly, sustainable option which complements the window’s natural timber construction.
By opting to use the new Woodwright® insert window, builders can now upgrade the overall performance and energy efficiency of their old sash windows to the same degree as the best full frame replacements, as low E argon filled double glazing and self cleaning glass is supplied as standard. Furthermore, as only the sash part of the original window is replaced, FENSA certification is not required.
In fact, for those properties, where full frame replacement is too radical and the option of repairing the original window is unviable, specification of the ‘insert replacement window’ represents a practical and cost effective option that could help save the British sliding sash window.
